Northern Hemisphere cold has been very pronounced threatening spring planting delays in Canada, United States and Northeast China. This is not an inclusive list of cold weather threats to crop yields, but rather the worst ones.

Unseasonably Cold in Midwest Corn Belt

Abnormal cold persisted last week in the northern United States and Canadian prairies, perpetuating worries about spring planting delays. On the positive side strong warming developed last week in the Eastern Midwest corn states Indiana and Ohio. This is a bright spot in an otherwise threatening cold spring. Corn planting delays are certain in Minnesota, South Dakota, Iowa and Nebraska where wave train of polar air masses have occurred this spring. Corn seeds need 52 F to germinate. Iowa soil temperatures April 14 were 37-40 F, the top U.S. corn state. Warming of frozen fields has been painfully slow, though soil temperatures have warmed up 7 degrees F since April 1.

U.S. Wheat Damage Feared From Hard Freeze

Last week a hard freeze on the High Plains threatened winter wheat occurring on 2 successive nights and causing temperatures as low as 18 F. Wheat was well along in the jointing stage, but not yet heading, the most critical period for freeze damage. Another hard freeze is possible Thursday morning in a fresh cold outbreak. Temperatures are expected to be relatively less extreme with lows from 24-30 F. The new forecast this week is very cold once again.

Spring Wheat Planting Still a Long Way Off

Fields are still frozen and snow covered in North Dakota and Western Minnesota, key spring wheat areas. In a northern climate where the growing season is relatively, any delays in planting are a threat to the crop. The North Dakota spring wheat planting in 2011 did not finish up until early June, due to sodden fields from a heavy snowmelt from a slow-developing spring. Severe planting delays had negative impact, the wheat harvest finishing up 33% below normal on sharply reduced plantings. Saskatchewan is still buried beneath a thick blanket of snow, Canada's leading wheat province. Winter weather was unusually stormy and cold. The last time Saskatchewan had such a thick snowpack was the 2006-07 winter season. This ultimately led to severely depressed plantings and a sharply reduced wheat harvest.

Abnormal China Cold Threatens Corn Planting

Persistent cold and slow melting snow in Northeast China has continued March into April posing a serious threat to spring corn planting. Producers usually begin planting in early May, but persistent snow from lasting cold would delay progress. The winter brought extra-heavy snow to the Northeast that, due to ongoing cold, has been slow to melt. Harbin the capital of Heilongjiang averaged 35-36 F last week. Severe planting delays from cold, wet fields would be negative for corn potential in the top China corn province that produces the highest yields. Abnormal cold is expected to persist another 3-4 days before temperatures gradually moderate.